Imidazolidinone derivatives in a composition and method for producing c.n.s.depressant effects

ABSTRACT

1-(2- OR 1-(3-(4-(4,5-Dihydrothieno(2,3-b)(1)benzothiepin-4-yl)1-piperazinyl)-alkyl) -3-alkyl-2-imidazolidinones and the pharmaceutically acceptable acid addition salts thereof which compounds exhibit depressant activity on the central nervous system; pharmaceutical compositions comprising these compounds and their salts as aforesaid and methods of producing central nervous system depressant effects in mammals which comprise administering an effective amount of a compound according to the invention or a pharmaceutically acceptable acid addition salt thereof; an illustrative embodiment is 1-(2-(4-(4,5dihydrothieno(2,3-b)(1)benzothiepin-4-yl)-1-piperazinyl)-ethyl)3-methyl-2-imidazolidinone.

United States Patent [191 Schindler et a1.

[ IMIDAZOLIDINONE DERIVATIVES IN A COMPOSITION AND METHOD FOR PRODUCING C.N.S. DEPRESSANT EFFECTS [75] Inventors: Walter Schindler, Riehen, near Basel; Armin Ziist, Birsfelden, near Basel, both of Switzerland [73] Assignee: Ciba-Geigy Corporation, Ardsley,

[22] Filed: Sept. 22, 1971 [21] Appl.No.: 182,878

Related US. Application Data [62] Division of Ser. No. 832,011, June 10, 1969, Pat. No.

[30] Foreign Application Priority Data June 20, 1968 Switzerland ..921 1/68 Dec. 23, 1968 Switzerland ..19149/68 [52] US. Cl ..424/250 [51] Int. Cl. ..A61k 27/00 [58] Field of Search ..424/250 1March 20, 1973 i l 7 References 7 OTHER PUBLICATIONS Beyaert et 2.1., Pr. AVad. Amsterdam, Vol. 42, pp. 716 789 (1939) Govaert et a1. Pr. AVad. Amsterdam, Vol. 42, pp. 790-797 (1939) Primary Examiner-Stanley J. Friedman Attorney-Karl F. Jorda et a1.

[5 7] ABSTRACT 2 Claims, N0 Drawings CROSS-REFERENCE TO RELATED APPLICATION This application is a divisional of Ser. No. 832,011, filed June 10,1969, now U. 5. Pat. No. 3,646,039.

The present invention relates to imidazolidinone derivatives, processes for their production, pharmaceutical compositions containing these compounds and the use thereof.

More particularly, the present invention relates to 1- [2- or 1-[3-[4-(4,5-dihydrothieno[2,3-b]benzothiepin- 4-yl)-1-piperazinyl]-alkyl]-3-alkyl-2-imidazolidinones of the formula I wherein R is alkyl having from 1 to 6 carbon atoms and n is 2 or 3 and the pharmaceutically acceptable acid addition salts thereof.

As alkyl R can be the methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec.butyl, tert.butyl, pentyl, 2-methy1butyl, isopentyl, 2,2-dimethylpropyl, 1- methylbutyl, l-ethylpropyl, 1,2-dimethylpropy1, tert.pentyl group or the n-hexyl group.

It has now been found that the aforementioned compounds have a marked central nervous system depressant effect in mammals on oral, rectal tranquilizing parenteral administration, e.g., they reduce motility, potentiate anesthesia and exhibit hypnotic action. They prevent reflexes, have a tranquilising effect on the fighting mouse and also exhibit antihistaminic action and sympathicolytic activity. Furthermore, they exhibit anti-emetic and hypothermic' action. In comparison with the central depressant properties, the new compounds have a small cataleptic inherent action. They are also effective in the test de la traction.

Accordingly, the present invention provides, in a further aspect, a pharmaceutical composition comprising an effective amount of a compound of the formula I or a pharmaceutically acceptable acid addition salt thereof together with an inert pharmaceutical carrier therefor, as well as a method for producing central nervous system depressant effects in mammals which comprises administe'ring to said mammal an effective amount of such a compound or pharmaceutically acceptable acid addition salt thereof. Administration is, e.g., oral, rectal or parenteral.

The pharmacological properties of the inventive compounds and salts can be determined by selected standard tests [c.p. R. Domenjoz and W. Theobald, Arch.Int.Pharmacodyn.I 450 (1959); W. Theobald et al., Arch. lnt.Pharmacodyn. I48, 560 (1946) and W. Theobald et al., Arzneimittelforsch.17, 361 (1967)] and characterize them as being suitable for the treatment of states of tension, agitation and hypernemesis. These tests also characterize the inventive compounds as being highly suitable for use as hypnotics.

For example, on intraperitoneal administration of about 0.33 mg/kg of l-[2-[4-(4,5-dihydrothieno[2,3-b] [1]-benzothiepin-4-yl)-l -piperazinyl]-ethyl]-3-methyl- Z-imidazolidinone bis-methane sulfonate to mice, the spontaneous orientation motility is found to decrease to a considerable extent. The same compound, administered in amounts of about 0.08 mg/kg subcutaneously to mice, prevents a considerable percentage of the animals, hanging on to a wire with their front paws, from pulling up and gripping the wire with their hind paws (test de la traction). Comparable results may be obtained on administration of l-[3-[4-(4,5- dihydrothieno[2,3-b] l ]benzothiepin-4-yl)-1- piperazinyll-propyl]-3-methyl-2-imidazolidinone dihydrochloride. The anesthesia potentiating activity of e.g. 1-[3-[4-(4,5-dihydrothieno[2,3-b][ l benzothiepin-4-yl)-1-piperazinyl]-propyl]-3-methyl-2- imidazolidinone dihydrochloride and 1-[2-[4-(4,5- dihydrothieno[2,3-b][1]-benzothiepin-4-yl)-1- piperazinyl]-ethyl]3-methyl-2-imidazolidinone bismethane sulfonate may be demonstrated by subcutaneous administration of respectively about 0.5 to 1.0 and 0.2 to 1.0 mg/kg of these compounds to mice, anesthetized by intraperitoneal injection of 40 mg/kg of the short-acting anesthetic N,N-diethyl-2-mcthoxy-4- allyl-phenoxy acetic acid amide. In both cases, the anesthetic effect of the N,N-diethyl-2-methoxy-4-allylphenoxyacetic acid amide is found to be prolonged to a very significant extent. The anti-emetic activity of the compound of the invention as determined in golden hamsters and dogs is very pronounced. The cataleptic activity, determined in rats, is found to be only moderate.

The hypnotic activity of the compounds of the present invention may be demonstrated by the observation test in mice [c.p. Samuel Irwin, Science 136, 123-128 (1962)]. In this test an ED of about 0.5 mg/kg may be observed on intraperitoneal injection of e.g. l-[3-[4-(4,5-dihydrothieno[2,3-b1[1] benzothiepin-4-yl)-l-piperazinyl]-propyl]-3-methyl-2- imidazolidinone dihydrochloride.

The toxicity of the compounds of the invention and their pharmaceutically acceptable acid addition salts as demonstrated in mice on intravenous administration is of favorably low order.

In addition to the two compounds, 1-[2-[4-(4,5- dihydrothieno[2,3-b][ l]benzothiepin-4-yl)-1-piperazinyl]-ethyl]-3-methyl-2-imidazolidinone and l-[3-[4- (4,5-dihydrothieno[2,3-b][1]benzothiepin-4-yl)-1- piperazinyl]-propyl]-3-methyl-2-imidazolidinone referred to above, which are especially preferred members of the group of compounds of this invention, the following are also of particular interest: l-[3-[4-(4,5- dihydrothieno[2,3-b][ l ]benzothiepin-4-yl)-1-piperazinyl]-propy1]-3-ethyl-2-imidazolidinone; 1-[2-[4-(4,5- dihydrothieno[2,3-b][1]benzothiepin-4-yl)-1-piperazinylj-ethyl]-3-ethyl-2-imidazolidinone; 1-[2-[4-(4,5-

dihydr0thieno[2,3-b][1]benzothiepin-4-yl)-l-piperazi-- nyl]-ethyl]-3-butyl-2-imidazolidinone and 1-[2-[4-(4,5 -dehydrothieno[2 ,3 -b][1]benzotliiepin-4-yl)-1 piperazinyl1-ethyl]-3-hexyl-2-imidazolidinone,

as well as the pharmaceutically acceptable acid addition salts thereof.

In each case as a pharmaceutically acceptable acid addition salt the dihydrochloride is of particular interest and in the case of the 1-[2-[4-(4,5-

dihydrothieno[2,3-b][ l ]benzothiepin-4-yl)-l-piperazinyl]-ethyl1-3-methyl-2-imidazolidinone, also the bismethane sulfonate.

To produce a compound of the formula I according to the invention, a reactive ester of a compound of the formula II wherein R and n have the meanings given under formula I, is reacted with 1-(4,5-dihydrothieno[2,3-b][ l]benzothiepin-4-yl)piperazine or with an alkali metal derivative thereof and, optionally, the reaction product is converted into an acid addition salt thereof.

Suitable reactive esters of the compounds of formula II are, e.g., the halides such as the chloride or bromide and also the sulfonic acid esters, such as the methane sulfonic acid ester or the or p-toluene sulfonic acid ester.

These esters are reacted with the 4-(l-piperazinyl)- 4,5-dihydrothieno[2,3-b][1]benzothiepin preferably in the presence of a solvent. Suitable solvents are those which are inert under the reaction conditions, e.g., hydrocarbons such as benzene or toluene, halogen hydrocarbons such as chloroform, ethereal liquids such as ether or dioxane, lower alkanones such as acetone or methylethyl ketone, as well as phosphoric acid amides, e.g., the triamide of hexamethyl phosphoric acid.

In the reaction, according to the invention, of one molecular equivalent of a reactive ester with one molecular equivalent of a free base, a molecular equivalent of acid is split off. This acid can be bound to excess 4-( l -piperazinyl)-4,5-dihydrothieno[2,3-b] l] benzothiepin, or also to the dibasic reaction product. Preferably, however, an acid-binding agent is added to the reaction mixture. Suitable acid-binding agents are, e.g., alkali metal carbonates such as sodium or potassium carbonate, also tertiary organic bases such as, e.g., pyridine, triethylamine or particularly N,N- diisopropylethylamine. Excess tertiary bases can also be used as solvent.

If, instead of using 4-( l-piperazinyl)-4,5- dihydrothieno[2,3-b][ l ]benzothiepin in the reaction according to the invention, an alkali metal derivative of this compound is used, e.g., a sodium, potassium or lithium derivative, then it is advantageous to perform the reaction in a hydrocarbon, e.g. in benzene or toluene.

Of the starting materials embraced by the reactive esters of hydroxy compounds of formula II, the l-(2- chloroethyl)- and the l-(3-chloropropyl)-3-methyl-2- imidazolidinone are known. Further compounds of this type can be produced analogously. The second reaction component, the 4-( l-piperazinyl)-4,5- dihydrothieno[2,3-b][l]benzothiepin, is produced for example as follows: starting with 4-chloro-4,5- dihydrothieno[2,3-b][1]benzothiepin, the latter is reacted in benzene with l-piperazine carboxylic acid ethyl ester to obtain the 4-(4,5-dihydrothieno[2,3-b][ l]benzothiepin-4-yl)-l-piperazine carboxylic acid ethyl ester which, with the aid of potassium hydroxide in ethanol, is hydrolyzed and decarboxylated.

Applying a second process according to the invention, a compound of the formula III wherein R and n have the meanings given under formula I, or an alkali metal derivative of such a compound, is reacted with a reactive ester of 4-hydroxy-4,5- dihydrothieno[2,3-b][l]benzothiepin and, optionally, the reaction product is converted into an acid addition salt thereof.

Suitable alkali metal derivatives of compounds of the formula III are, e.g., sodium, potassium or lithium derivatives. Suitable reactive esters of the 4-hydroxy- 4,5-dihydrothieno [2,3-b][l ]benzothiepin are, e.g., the halides such as the chloride or bromide, also the sulfonic acid esters such as the methane sulfonic acid ester or the 0- or p-toluene sulfonic acid ester.

The reaction, according to the invention, of the free bases of the formula III, or of their alkali metal derivatives, with the reactive esters of the 4-hydroxy-4,5- dihydrothieno[2,3-b][ l ]benzothiepin, can be performed in the same solvents as mentioned in the first process.

If the free bases are used for the reaction, then the same acid-binding agents can also be used.

The starting materials of the formula III are described in the literature. Furthermore, the 4-chloro- 4,5-dihydrothieno [2,3-b][ l ]benzothiepin, which is an example for the second reaction component is likewise known. The corresponding 4-bromo-4,5- dihydrothieno[2,3-n][ l ]benzothiepin can be produced analogously.

Optionally, the compounds of formula I, obtained as above, are subsequently converted in the usual manner into their addition salts with inorganic and organic acids. For example, to a solution of a compound of the formula I in an organic solvent is added the acid, desired as the salt component, or a solution thereof. Those organic solvents are preferably chosen for the reaction in which the obtained salt is only slightly soluble, so that it can be separated by filtration. Such solvents are, e.g., methanol, acetone, methylethyl ketone, acetone/ethanol, methanol/ether or ethanol/ether.

For use as medicaments it is possible to use, instead of free bases, the pharmaceutically acceptable acid ad dition salts, i.e. salts with acids, the anions of which are not toxic in the case of the dosages in question. Furthermore, it is of advantage is the salts, used as medicaments, readily crystallize and are not, or are only slightly hydroscopic. For salt formation with compounds of the formula I, it is possible to use, e.g., hydrochloric acid, hydrobromic acid, sulfuric acid, phosphoric acid, methane sulfonic acid, ethane sulfonic acid, B-hydroxyethane sulfonic acid, acetic acid, malic acid, tartaric acid, citric acid, lactic acid, oxalic acid, succinic acid, fumaric acid, maleic acid, benzoic acid, salicylic acid, phenylacetic acid, mandelic acid and embonic acid.

The new active substances, as mentioned above, are administered e.g. orally, rectally or parenterally. Dosage amounts depend on the mode of administration, the species, age and weight of the animal and on the condition to be treated. Generally, the daily dosages of the free bases, or of pharmaceutically acceptable acid addition salts thereof, will vary between 0.05 mg/kg and 10.5 mg/kg for warm-blooded mammals. Suitable dosage units such as dragees, tablets, suppositories or ampoules, preferably contain 5-200 mg of an active substance, according to the invention or of a pharmaceutically acceptable salt thereof.

Dosage units for oral administration preferably contain as active substance between 1 and 90 percent of a compound of the formula I or of a pharmaceutically acceptable acid addition salt of a such like compound. They are produced by combining the active substance, e.g., with solid, pulverulent carriers such as lactose, saccharose, sorbitol, mannitol; starches such as potato starch, maize starch or amylpectin, also laminaria powder or citrus pulp powder; cellulose derivatives or gelatine, optionally with the addition of lubricants, such as magnesium or calcium stearate or polyethylene glycols, to form tablets or dragee cores. The latter are coated, e.g., with concentrated sugar solutions, which can also contain, e.g., gum arabic, talcum and/or titanium dioxide, or with a lacquer dissolved in easily volatile organic solvents or mixtures of solvents. Dyestuffs can be added to these coatings, e.g., to distinguish between varying dosages of active substance.

Other suitable dosage units for oral administration are hard gelatine capsules as well as soft, closed capsules made of gelatine and a softener such as glycerin. The hard capsules preferably contain the active substance as a granulate, e.g., in admixture with fillers such as maize starch, and/or lubricants such as talcum or magnesium stearate and, optionally, stabilizers such as sodium metabisulphite Na,s,o, or ascorbic acid. In soft capsules, the active substance is preferably dissolved or suspended in suitable liquids such as liquid polyethylene glycols, whereby stabilizers can also be added.

Suitable dosage units for rectal administration are e.g., suppositories consisting of a combination of an active substance, or of a suitable salt thereof, with a suppository foundation substance. Suitable as such are, e.g., natural or synthetic triglycerides, paraffin hydrocarbons, polyethylene glycols or higher alkanols. Also suitable are gelatine rectal capsules consisting of a combination of the active substance, or of a suitable salt thereof, and a foundation substance. Examples of the latter are liquid triglycerides, polyethylene glycols or paraffin hydrocarbons.

Ampoules for parenteral, especially intramuscular administration, preferably contain a water-soluble salt of an active substance in a concentration of preferably 0.5 to 5 percent, optionally together with suitable stabilizing agents and buffer substances, in an aqueous solution. I

The following examples further illustrate the production of the new compounds of the formula 1 and of intermediate products not described hitherto, but the examples in no way limit the scope of the invention. The temperatures are given in degrees Centigrade.

Example 1 a. 14.6 g (0.05 mol) of 1-(4,5-dihydro-thieno[2,3- b][1]benzothiepin-4-yl)piperazin are dissolved in 100 ml of methyl ethyl ketone. To this solution are added 13.8 g (0.1 mol) of potassium carbonate and 10.0 g (0.06 mol) of 1-(2-chloroethy1-3-methyl 2- imidazolidinone are added dropwise at 4050 to the reaction mixture. The mixture is refluxed, while stirring well, for 20 hours. The crude product slowly crystallizes out. The suspension is cooled to l. The precipitate is then filtered with suction, suspended in water, the suspension stirred, the crude product filtered with suction and then recrystallized from a large amount of acetone. The obtained l-[2-[4-(4,5- dihydrothieno[2,3-b][ 1]benzothiepin-4-yl)-1piperazinyl]ethyl]3methyl-2-imidazolidinone melts at 180-182.

14.0 g of the obtained base are dissolved in 100 ml of hot ethanol and neutralized with 2 molecular equivalents of ethanolic hydrochloric acid. 50 ml of acetic acid ethyl ester are added and the mixture is cooled to 5". The hydrochloride, which has crystallized out, is filtered off with suction, washed with a little cold ethanol, dried in vacuo at 100 and is then recrystallized from absolute ethanol. The obtained hydrochloride of the l-[2-[4-(4,5-dihydrothieno[2,3- b][1]benzothiepin-4yl)-l-piperazinyl]-ethyl]-3- methyl-Z-imidazolidinone melts at 210.

For the formation of the bis-methane sulfonate salt, 10.7 g (0.025 mol) of the base are dissolved in a hot mixture of ml of benzene and 20 ml of methylethyl ketone and treated with a solution of 4.8 g (0.05 mol) of methane sulfonic acid in 10 ml of methylethyl ketone. After the addition of 50 ml of absolute diethyl ether, the product which crystallizes is separated by filtration and recrystallized from ethanol/ethyl acetate. The pure l-[2-[4-(4,5-dihydro-thieno[2,3-b][ 1] benzothiepin-4-yl)-1 piperazinyl]-ethyl]-3-methyl-2- imidazolidinone-bismethane sulfonate melts at 182- 184.

The starting compound, i.e., the 1-(4,5- dihydrothieno [2,3-b][ l ]benzothiepin-4yl)-piperazin is produced as follows:

b. 12.6 g (0.05 mol) of 4-chlorothieno[2,3-b][l ]benzothiepin are added to a solution of 23.6 g (0.15 mol) of 1-piperazine carboxylic acid ethyl ester in 20 ml of benzene. The mixture is refluxed for 5 hours, taken up in 200 ml of water and 5 ml of concentrated sodium hydroxide solution and extracted with ether/methylene chloride (2:1). The organic phase is washed four times with water, dried over magnesium sulfate and is then concentrated by evaporation in vacuo. The obtained crude 4-(4,5-dihydrothieno[2,3- b][ 1 ]benzothiepin-4-yl)-1piperazine carboxylic acid ester melts at 1 18-l25 and the pure compound, after recrystallization from isopropanol/petroleum ether, at l36-138.

c. 10.4 g (0.0278 mol) of the ester, obtained according to b), are added to a solution of 18 g (0.316 mol) of potassium hydroxide in ml of absolute ethanol. The mixtureis refluxed for 12 hours, diluted with 50 ml of water, the ethanol evaporated off in vacuo and the residue extracted with ether/methylenechloride (2:1 The organic phase is dried over magnesium sulfate and concentrated by evaporation in vacuo. The residue is recrystallized from ligroin/acetic acid ethyl ester, whereupon the l-(4,5-dihydrothieno[2,3-b][ l]benziothiepin-4-yl)-piperazin melts at 126l28.

Example 2 a. 25.0 g (0.1 mol) of 4-chloro-4,S-dihydrothieno [2,3-b][l]benzothiepin are dissolved in 50 ml of hexamethyl phosphoric acid triamide. To this solution are added 42.0 g (0.2 mol) of 1-[2-(l-piperazinyl)-ethyl]-3 -methyl-2-imidazolidinone in 50 ml of absolute benzene. The solution is heated for 20 hours to 80, cooled to 20 and poured on to ice. The reaction mixture is extracted with acetic acid ethyl ester and the organic phase extracted six times with 2N hydrochloric acid. The clear, acid solutions are made alkaline with concentrated ammonia, the precipitated crystals filtered off with suction, washed with water and recrystallized from a large amount of acetone. The obtained 1- [2-[4-(4,5dihydrothieno[2,3-b][1]benzothiepin-4-yl)- 1-piperazinyl]-ethyl]-3-methyl-2-imidazolidinone melts at l80182.

The same end product can also be obtained as follows:

b. 10.6 g (0.05 mol) of l-[2-(l-piperazinyl)-ethyl]-3- methyl-2-imidazolidinone are dissolved in 50 ml of absolute benzene, and a solution of 3.2 g (0.05mol) of butyl lithium in hexane is added dropwise at thereto. The reaction mixture is brought to room temperature and stirred for 1 hour at 40. After cooling again to 0, a solution of 12.6 g (0.05 mol) of 4-chloro-4,5-dihydrothieno[2,3-b] [1]benzothiepin in 40 ml of absolute benzene is added dropwise during 30 minutes. The reaction mixture is warmed to room temperature within 1 hour and then refluxed for 4 hours.

The mixture is then poured into 200 ml of ice water, treated with 25 ml of 2 N sodium hydroxide solution and shaken out with benzene. The combined benzene extracts are shaken out with 200 ml of a 1 molar solution of methane sulfonic acid, and the acidic aqueous phase is then alkalized with concentrated sodium hydroxide solution and again extracted with benzene. The resulting benzene extracts are washed with water, dried over magnesium sulfate, and .the solvent is removed in vacuo. The resulting residue is recrystalized from benzene/petroleum ether. The pure l-[2-[4-(4,5- dihydro-thieno [2,3-b][1]benzothiepin-4-yl)-lpiperazinyl]-ethyl]-3-methyl-Z-imidazolidinone melts at 180-182.

The following reaction also yields the same end product:

c. l 1.7 g (0.05 mol) of 4-hydroxy-4,5-dihydrothieno[2,3-b] [1]benzothiepin and 4.75 g (0.06 mol) of pyridine are dissolved in 50 ml of absolute toluene, and during the course of 30 minutes a solution of 507 g (0.05 mol) of methane sulfonic acid chloride in ml of absolute toluene are added dropwise at l0. The mixture is stirred for 2 hours at l0 and then added dropwise at 0 to a solution of 21.2 g (0.1 mol) of l-[2- (1-piperazinyl)-ethyl]-3-methyl-2-imidazolidinone in 50 ml of absolute benzene. The reaction mixture is then warmed to room temperature during the course of 1 hour and then refluxed for 4 hours.

The mixture is poured into 200 ml of ice water and processed further as described under (b). The resulting l-[2-[4-(4,5-dihydro-thieno[2,3-b] [1]benzothiepin-4- yl)-l-piperazinyl]-ethyl1-3-methyl-2-imidazolidinone is identical to the product obtained under (a) and (b) and melts at 180l82.

Example 3 9.5 g (0.03 mol) of 1-(4,5-dihydrothieno[2,3-b][ l]benzothiepin-4-yl)-piperazine are refluxed with 6.35 g (0.036 mol) of 1-(3-chloropropyl)-3-methyl-2- imidazolidinone and 8.3 g (0.06 mol) of potassium carbonate for 36 hours in ml of diethyl ketone. The reaction mixture is then poured on to 200 ml of ice water, 40 ml of 2N sodium hydroxide solution are added and the mixture is extracted with chloroform. The organic extract is washed with water, dried over magnesium sulfate and concentrated by evaporation in vacuo.

The crude base is dissolved in 50 ml of acetone and ethereal hydrochloric acid is added to the acetone solution until an acid reaction is shown on congo paper. The crude dihydrochloride, which precipitates, is filtered, washed with acetone and also-with ether, and dried in vacuo. After recrystallization of the crude product from 96 percent ethanol/ether, the pure l-[3- [4-(4,5-dihydrothieno[ 2,3-b][ l ]benzothiepin-4-yl)-l piperazinyl]-propyl]-3-methyI-Z-imidazolidinone dihydrochloride, M.P. l89l92, is obtained.

Example 4 a. 12.05 g (0.04 mol) of 1-(4,5-dihydrothieno[2,3- b][l]benzothiepin-4-yl)-piperazin and 9.15 g (0.048 mol) of l-(3-chloropropyl)-3-ethyl-2-imidazolidinone are dissolved in 100 ml of diethyl ketone and 11.0 g (0.08 mol) of potassium carbonate added. The reaction mixture is refluxed for 24 hours, poured on to 200 ml of ice water and 50 ml of 2N sodium hydroxide solution are added. The organic phase is separated and the aqueous alkaline solution extracted with ether/methylene chloride (2:1 The organic solutions are combined, washed with water and extracted with 250 ml of molar methane sulfonic acid solution. The acid extract is made alkaline with concentrated sodium hydroxide solution and the precipitated, crude base shaken out with 200 ml of ether/methylene chloride (2:1). The extract is washed with water. dried over magnesium sulfate and concentrated by evaporation in vacuo.

The residue is dissolved in 50 ml of acetone, [50 ml of absolute ether are added and the dihydrochloride is precipitated with ethereal hydrochloric acid. The dihydrochloride is filtered off, washed with acetone and ether, dried in vacuo and recrystallized from 96 percent ethanol/ether. The obtained pure l-[3-[4-(4,5- dihydrothieno[2,3-b][ l ]benzothiepin-4-yl)-1-piperazinyll-propyl]-3-ethyl-2-imidazolidinone dihydrochloride melts at -177.

The l-(3-chloropropyl)-3-ethyl-2-imidazolidinone, used as starting material, is produced as follows:

b. 60.0 g (0.52 mol) of 3-ethyl-2-oxazolidinone and 68.1 g (0.57 mol) of (3-chloropropyl)-isocyanate are mixed with 4.8 g of lithium chloride and the mixture is heated for 90 minutes to l75l80. The reaction mixture is cooled and 300 ml of chloroform are added. The chloroform solution is separated, washed three times with, each time, 30 ml of saturated sodium chloride solution, dried over magnesium sulfate and concentrated by evaporation in vacuo. The residue is distilled under high vacuum and the pure l-(3-chloropropyl)-3- ethyI-Z-imidazolidinone, B.P. 105110/0.01 Torr; un is obtained.

Example a. Analogously to Example 4 a) is obtained the following end product: from 10.6 g (0.035 mol) of 1-(4,5- dihydrothieno [2,3-b][1 ]benzothiepin-4-yl)-piperazin and 7.4 g (0.042 mol) of 1-(2-chloroethyl)-3-ethyl-2- imidazolidinone is obtained the l-[2-[4-(4,5- dihydrothieno[2,3-b][1]benzothiepin-4-yl)-l-piperazinyl]-ethyl]-3-ethyl-2-imidazolidinone, M.P. l22l 24; dihydrochloride M.P. 187189.

b. 115 g (1.0 mol) of 3-ethy1-2-oxazolidinone and 116 g (1.1 mol) of (2-chloroethyl)-isocyanate are mixed with 10.0 g of lithium chloride and heated from 2 hours to 180. The reaction mixture is cooled, 300 ml of chloroform are added and the mixture is extracted three times using 30 ml of saturated sodium chloride solution each time. The organic phase is dried over magnesium sulfate and concentrated by evaporation in vacuo. The oily residue is distilled under high vacuum. The obtained pure l-(2-chloroethyl)-3-ethyl-2- imidazolidinone boils at 95/0.01 Torr; 23 1.4913.

Example 6 Analogously to Example 4a, the following end product is obtained:

From 12.8 g (0.04 mol) of 1-(4,5-dihydro-thieno[ 2,3-b] [l]-benzothiepin-4-yl)-piperazine and 9.8 g (0.048 mol) of l-(2chloroethyl)-3-buty1-2- imidazolidinone there is obtained 1-[2-[4-(4,5- dihydro-thieno[2,3-b][1]benzothiepin-4-yl)-l-' piperazinyl]-ethyl]-3-butyl-2-imidazolidinone, the dihydrochloride sesquihydrate of which melts at 191-193.

Example 7 a. Analogously to Example 4a, the following end product is obtained:

From 12.8 g (0.04 -b] mol) of 1-(4,5-dihydro-thieno[ 2,3-][l]benzothiepin-4-yl)-1-piperazine and 11.2 g (0.048 mol) of imidazolidinone, the 1-[2-[4-(4,5-dihydro-thieno[2,3- b] l ]benzothiepin-4-yl)-l -piperazinyl]-ethyl]-3-nhexyl-2-imidazolidinone having a melting point of 9395, dihydrochloride l92-195.

'The 1-(2-chloroethyl)-3-n-hexyl-2-imidazolidinone, used as starting material, is produced as follows:

b. 77.6 g (0.5 mol) of n-hexylamino-ethanol with 65.0 g (0.55 mol) of diethyl carbonate and l g of sodium are slowly heated to reflux temperature. The ethanol liberated during the reaction is continuously distilled over a column for a period of 2 hours. The residue is rectified in high vacuum. The pure S-n-hexyl- 2-oxazolidinone boils at 100/0.005 Torr, n 1.4564.

c. 51.3 g (0.3 mol) of the product obtained according to (b) are heated for about 2 hours at 180 with 34.8 g (0.33 mol) of (2-chloroethyl)-isocyanate and 2.4 g of lithium chloride. After cooling, the reaction mixture with the addition of 30 ml of saturated sodium 1-(2-chloroethyl)--n-hexyl-2- chloride solution is shaken out with 300 ml of chloroform. The organic phase is dried over magnesium sulfate, the solvent is removed in vacuo and the residue is rectified in high vacuum. The resultant, pure 1-(2-chloroethyl)-3-n-hexyl-2-imidazolidinone boils at 12l127/0.02 Torr, n 1.4818.

Example 8 a. Analogously to Example 2, from 12.6 g (0.05 mol) of 4-chloro-4,5-dihydro-thieno[2,3-b][1]benzothiepin and 25.4 g (0.1 mol) of 1-[2-(1-piperazinyl)-ethyl]-3- butyl-Z-imidazolidinone there is produced the 1-[2-[4- (4,5-dihydro-thieno[ 2,3-b][ l ]benzothiepin-4-yl)- l piperazinyl]-ethyl]-3-butyl-2-imidazolidinonedihydrochloride-sesquihydrate, m.p. 191193.

The l-[2-(1-piperazinly)-ethyl]-3-butyl-2- imidazolidinone required as starting material is obtained as follows:

b. 40.4 g (0.2 mol) of l-(2)-chloroethyl)-3-butyl-2- imidazolidinone are dissolved with 35.0 g (0.22 mol) of carbethoxypiperazine in 200 ml of diethyl ketone and, with the addition of 55.3 g (0.4 mol) of finely powdered potassium carbonate, are refluxed for 24 hours, cooled and The the residue is extracted by boiling twice with 200 ml each of chloroform and filtered.

The combined filtrates are concentrated to dryness in vacuo, and the oily residue is distilled in high vacuum. The pure 1-[2-(N-carbethoxy-piperazinyl) ethyl]-3-butyl-2-imidazolidinone boils at 190192 /0.01 Torr, n,, 1.4941.

c. 54.0 g (0.164 mol) of 1-[2-(N-carbethoxypiperazinyl-ethyl]-3-butyl-2imidazolidinone are refluxed for 16 hours with a solution of 60 g of potassium hydroxide in 300 ml of absolute ethanol. The resulting precipitate is filtered and rinsed with hot ethanol. The combined filtrates are then concentrated to dryness. The residue is taken up in 300 ml of benzene and ml of water; after separation, the aqueous phase is saturated with potassium carbonate and extracted 4 times with benzene. The combined benzene solutions are dried over potassium carbonate and freed of solvent in vacuo. The residue is distilled in high vacuum, whereby the pure 1[2-(1-piperazinyl)-ethy1]-3-butyl-2- imidazolidinone passes over at -160/0.01 Torr; n,,= 1.5033.

Example 9 Analogously to example 2, from 12.6 g (0.05 mol) of 4-ch1oro-4,5-dihydro-thieno[2 ,3-b][1]benzothiepin and 28.2 g (0.1 mol) of 1-[2-(1-piperazinyl)-ethyl]-3- n-hexyl-2-imidazo-lidinone, there is obtained l-[2-[4-(4,5-dihydro-thieno[2,3-b][1]benzothiepin- 4yl)-l-piperazinyl]-ethyl]-3n-hexyl-2imidazolidinone, m.p. 92-95, dihydrochloride 192195.

The imidazolidinone derivative required as starting material is obtained analogously to Example 8 b) and c).

Example 10 250 g of 1-[2-[4-(4,5-dihydrothieno[2,3-b][1] benzothiepin-4-yl)-1-piperazinyl]-ethyl]-3-methyl-2- imidazolidinone are mixed with 175.80 g of lactose and 169.70 g of potato starch. The mixture is moistened with an alcoholic solution of 10 g of stearic acid and is then granulated through a sieve. After drying, 160 g of potato starch, 200 g of talcum. 2.50 g of magnesium stearate and 32 g of colloidal silicon dioxide are mixed in. The obtained mixture is pressed into 10,000 tablets each weighing 100 mg and each containing 25 mg of active substance. Optionally, the tablets can be provided with grooves for more accurate adjustment of the dosage amount.

Example 1 l A granulate is produced from 250 g of 1-[2-[4-(4,5- dihydrothieno[2,3-b][ l ]benzothiepin-4-yl)-l -piperazinyl]-ethyl]-3-methyl-2-imidazolidinone, 175.90 g of lactose and an alcoholic solution of g of stearic acid. After drying, the granulate is mixed with 56.60 g of colloidal silicon dioxide, 165 g of talcum, g of potato starch and 2.50 g of magnesium stearate, the mixture then being pressed into 10,000 dragee cores. These are subsequently coated with a concentrated syrup made from 502.28 g of crystallized saccharose, 6 g of shellac, 10 g of gum arabic, 0.22 g of dyestuff and 1.5 g of titanium dioxide, and dried. The obtained dragees each weigh 120 mg and each contain mg of active substance. 1

Example 12 To produce 1,000 capsules each containing mg of active substance, 25 g of 1-[3-[4-(4,5- dihydrothieno[2,3-b][ l ]benzothiepin-4-yl)-l-piperazinyl]-propyl]-3-methyl-2-imidazolidinone are mixed with 248.0 g of lactose. The mixture is evenly moistened with an aqueous solution of 2.0 g of gelatine and granulated through a suitable sieve (e.g., Sieve III, Ph.Helv. V). The granulate is mixed with 10.0 g of dried maize starch and 15.0 g of talcum and the obtained mixture is uniformly filled into 1,000 hard gelatine capsules, size 1.

Example 13 A suppository foundation mixture is prepared from g of l-[3-[4(4,5-dihydrothieno[2,3-b][11 benzothiepin-4-yl)- l -piperazinyl]-propyl]-3-methyl 2imidazolidinone and 167.5 g of adeps solidus. From this mixture are then filled suppositories each containing 25 mg of active substance.

Example 14 A solution of 25 g of l-[2-[4-(4,5-dihydrothieno [2,3-b][1]benzothiepin-4-yl)-l-piperazinyl]-ethyl]-3- methyl-2-imidazolidinone dihydrochloride in one liter of water is filled into 1,000 ampoules and sterilized. An ampoule contains a 2.5 percent solution of 25 mg of active substance.

What is claimed is:

1. A pharmaceutical composition comprising a central nervous system depressing amount of a compound of the formula 1 S N N-(cH2)n'N N-R wherein R is alkyl having from one to six carbon atoms and n is 2 or 3 or a pharmaceutically acceptable acid addition salt thereof together with an inert pharmaceutical carrier therefor.

2. A method for producing central nervous system depressing effects in a mammal which comprises administering to said mammal a central nervous system depressing amount of a compound as defined in claim 1 or a pharmaceutically acceptable acid addition salt thereof. 

2. A method for producing central nervous system depressing effects in a mammal which comprises administering to said mammal a central nervous system depressing amount of a compound as defined in claim 1 or a pharmaceutically acceptable acid addition salt thereof. 